Welcome aboard!
I just did a search and found their site (fireworks company) from the photo it looks
substantial enough, would like to have seen more than 3/4" thickness in the base,
by taper you mean the "V" left by the drill bit?
just re-read the other post and see it's from the drill bit, when building a chamber
we like to see rounded surfaces, the corner's create a weak point, in a noise maker
not as much of a problem as in a cannon or mortar shooting ball.